53 How do I write the correlation coefficient?

The correlation coefficient is a formula used to measure the strength of the relationship between the relative changes in two variables.

The following video describes how to write one version of the correlation coefficient:

Note that the video says that the way to write the sigma in the equation is to use the command \Sigma. While this will produce a sigma, another command that will do the same is \sum. The \sum command produces a larger sigma that is more suitable for such an equation.